Research Of Microseismic Source Location Methods Based On Polarization Analysis

As the current mining and mining safety monitoring in the areas of emerging energy technology, microseismic monitoring technology has become one of the hot technology of earth physics, microseismic monitoring method response information timeliness, richness, accuracy is unmatched by other methods. Microseismic monitoring in shale gas and traditional oil and gas, mainly produced in the process of using hydraulic fracturing of microseismic events, to correctly reflect the spatial distribution of fracturing cracks and geometric shape, so as to guide and optimize design of oil and gas recovery; While in the mining safety monitoring, mainly through statistical mine mining caused by density and spatial distribution of the seismic event, further delineating hazard area to guide production. Combine elements from the application of microseismic monitoring, it is not hard to see the accurate seismic source localization microseismic monitoring technology is an important foundation for application in many fields, and the effective source locating method is one of the important factors that affect the positioning accuracy.This paper developped the feasibility of optimization design by integrating various parts,based On previous research of microtremor technology,Combining the advantages and disadvantages of mainstream seismic equipment both at home and abroad, giving full consideration to the current seismic method problems and using the idea of modular design. Then divided the research on the positioning algorithm of microtremor into azimuth data access and correction and the source location of two functional units. At the same time finished the integrated the function of the whole system by combining the function of application development needs and perfecting the software function. The whole paper mainly completed the following works:(1)Studied the multi-wave propagation theory in complex mountainous region medium, and calculated wave motion equation and the boundary of the irregular surface to absorb more conditions by adopting finite difference method, achieved the multi-wave field forward numerical modeling finally. In this part, firstly, we built the multi-wave(p-wave and converted wave) wave equation of explicit difference scheme by approximating partial derivative of the wave equation with the center difference quotient. Secondly, we putted forward a kind of efficient PML algorithm to eliminate the boundary of the irregular surface effects based on the SPML(split type exactly match) method and the NPML(not divide exactly match) method. Finally, we established the theoretical model of complex mountainous terrain on the basis of Marmousi model and analyze the result of seismic wave field numerical simulation.(2)Finished the research of Vibration analysis method theory.First analyzed the polarization projection method,introduced Three-component seismic data transmission and polarization characteristics, proposed Three-component waveform calculation method of the polarization direction.And This part designed the polarization analysis method of source localization by using the principle of adaptive window length method,then verified the polarization analysis method based on adaptive covariance matrix Through the numerical simulation experiment.(3)Finished the Analysis and improvement of the time difference method.This part described the principle of first-break picking in detail,and then designed the method of the accurate first-break picking based on the energy ratio method and wavelet analysis.Finally,this part designed the exhaustive grid search method of optimization constraints based on the traditional time difference method to improve the analysis, could largely reduce the time complexity of the time difference method.(4)Designed the Joint positioning method of Microseismic Source Location based on Polarization analysis. First, this part designed the seismic three-component geophone attitude detection scheme, calculated the detector of random orientation information Through a combination of hardware and software;then this part designed the correction algorithm of detector based on the geophone orientation information and could isolate the source of the direction of propagation by putting a three-component data correction to the direction of the source and detector attachment. Finally, the part setted up a joint positioning method through joint improvement time positioning method and polarization analysis method,could calculate seismic source location in the more complex geological conditions.(5)The Microseismic Source Location Methods based on Polarization analysis developed was successfully applied to a coal mine area. We started the work about the demolition and Microseismic monitoring,which contains the detector correction of collect data, first-break picking and so on. At the same time the paper used three different localization algorithm to calculate the shot point and comparativly analysis, then did statistical analysis about the test area of the break point and Seismic focal point.The main innovation of this article is that:(1)Based on the three-dimensional coordinate rotation algorithm, this paper puts forward a kind of inertial sensor group orientation information as input parameters of three-component data correction methods.(2)In view of the microseismic monitoring of low signal noise ratio(SNR), unable to accurately identify the seismic events and the long time monitoring, then detector is bad, this paper puts forward a kind of based on polarization analysis and unite time difference of the source localization method, can be achieved for a small amount of geophone and weak signal source localization.